Traitor tracing systems help content distributors to identify pirates. For example, consider an encrypted satellite radio broadcast that should only be played on certified decoders (e.g., radio receivers). The broadcast is encrypted using a public broadcasting key, BK. Any certified decoder can decrypt the broadcast using an embedded private key, Ki. However, there is also the risk that a pirate can compromise a certified decoder and extract the private key, Ki. The pirate could then build a pirate decoder that will extract the cleartext content from the encrypted broadcast using the extracted private key, Ki. The pirate could even make the pirate decoder widely available so that anyone can extract the cleartext content for themselves.
Thus, there is a need in the art for a method and apparatus for traitor tracing.